The walls of Tate Modern are to be adorned with comic strips and advertising images as the gallery exhibits the works of Roy Lichtenstein.
Speaking to ITV News, Vladimir Umanets, insisted he was not a vandal and was being "unfairly attacked" over the writing on the Rothko mural.
The first major survey of Hirst's work ever held in the UK, has opened at the Tate Modern in London.
Vladimir Umanets declined to reveal where he lives. But he said he knew he would probably be arrested:
I believe that from everything bad there's always a good outcome so I'm prepared for that but obviously I don't want to spend a few months, even a few weeks, in jail. But I do strongly believe in what I am doing, I have dedicated my life to this.
Umanets is one of the founders of "Yellowism". He describes as "neither art, nor anti-art":
Yellowism is not art, and Yellowish isn't anti-art. It's an element of contemporary visual culture. It's not an artistic movement. It's not art, it's not reality, it's just Yellowism.
It can't be presented in a gallery of art, it can be presented only in a Yellowistic chambers. The main difference between Yellowism and art is that in art you have got freedom of interpretation, in Yellowism you don't have freedom of interpretation, everything is about Yellowism, that's it. I am a Yellowist.
I believe what I am doing and I want people to start talking about this. It was like a platform. I don't need to be famous, I don't want money, I don't want fame, I'm not seeking seeking attention. Maybe I would like to point people's attention on what it's all about, what is Yellowism, what is art?
A man has admitted writing on a Mark Rothko work at the Tate Modern in London, but insists he is not a vandal. The writing on the bottom-right corner of the piece appears to read: "Vladimir Umanets, A Potential Piece of Yellowism."
Today, Mr Umanets, who is originally from Russia, claimed he had written on the painting, saying:
– Vladimir Umanets
Some people think I'm crazy or a vandal, but my intention was not to destroy or decrease the value, or to go crazy. I am not a vandal."
Police are hunting for a vandal defaced a painting by Mark Rothko at the Tate Modern art gallery.
Eyewitness Tim Wright said: "This guy calmly walked up, took out a marker pen and tagged it. Surreal."
A picture he uploaded to the social networking website showed five or six words scrawled on the bottom-right corner of the piece, with black streaks of paint running down from the daubed writing.
They appear to read: "Vladimir Umanets, A Potential Piece of Yellowism."
Police are hunting for a vandal who walked into the Tate Modern art gallery and defaced a valuable painting by Mark Rothko.
The visitor daubed black paint on the mural piece during a visit to the popular landmark yesterday afternoon, a spokeswoman for the gallery said.
The art gallery said it does not have a price for the defaced piece, but paintings by the Russian-born artist often fetch tens of millions of pounds.
Earlier this year, Rothko's Orange, red, yellow was sold for £53.8 million - the highest price ever paid for a piece of post-war art at auction in New York.
Scotland Yard confirmed it had launched an investigation into the matter and is yet to make any arrests.
The force said it was looking for a white male in his late 20s.
A painting by Mark Rothko has been defaced at the Tate Modern art gallery.
Police were called after a small area of the mural piece was painted, a spokeswoman for the gallery said.
– Tate Modern spokeswoman
Tate can confirm that at 3.25pm this afternoon, there was an incident at Tate Modern in which a visitor defaced one of Rothko's Seagram murals by applying a small area of black paint with a brush to the painting. The police are currently investigating the incident.
The gallery was shut for a short period and then reopened.